I need My 2020 AiG

Your 2020 AGI is shown on line 11 of your 2020 Form 1040.  But why do you want it?   It is too late for you to e-file a 2021 tax return, so you do not need AGI for that.  The only way to file a 2021 tax return now is by mail.  E-filing for 2021 is permanently closed.

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.

Federal and state returns must be in separate envelopes and they are mailed to different addresses.  Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.

If you still want your 2020 AGI for some other reason:

Where do I find my AGI?

https://ttlc.intuit.com/community/agi/help/how-do-i-find-last-year-s-agi/01/25947

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/00/27010/message-id/746

Your 2020 tax return shows your 2020 Adjusted Gross Income  (AGI)  If you filed a joint return then the AGI is the same for each of you.

Form 1040        line 11

If you are using the same TT account that you used last year, you should also be able to find this number in your Tax Home for 2020

If entering the amount from your 2020 tax return does not work, then try entering “0” instead.  If that does not work and you still cannot e-file, then print, sign, and mail your tax return.

You can get a free transcript of your past return from the IRS:  

https://www.irs.gov/individuals/get-transcript